Auto-download composer dependencies for php script

phps.php

#!/usr/bin/env php
<?php
declare(strict_types=1);

const PHPS = 'phps';
const COMMENT = '#';
const BANG = '!';

if (empty($argv[1])) {
    throw new RuntimeException("Missing php file");
}

$file = realpath($argv[1]);
if ($file === false) {
    throw new RuntimeException("No such file {$argv[1]}");
}

function scanner(string $file): Generator
{
    $fp = fopen($file, 'rb');
    $found = false;
    do {
        $line = fgets($fp);
        if ($line === false) {
            break;
        }
        if ($line[0] === COMMENT && $line[1] !== BANG) {
            $found = true;
            yield $line;
        } else if ($found === true) {
            break;
        }
    } while (true);
    fclose($fp);
}

function parser(Generator $scanner): Generator
{
    foreach ($scanner as $line) {
        $result = explode(PHPS, $line, 2);
        if (isset($result[1])) {
            yield trim($result[1]);
        }
    }
}

$scanner = scanner($file);
$parser = parser($scanner);

$dirname = md5($file);
$dir = sys_get_temp_dir() . '/' . PHPS . "/{$dirname}";

$dependencies = [];

$composer_json = "{$dir}/composer.json";
if (is_file($composer_json)) {
    $json = file_get_contents($composer_json);
    $data = json_decode($json);
    if (isset($data->require)) {
        foreach ($parser as $instruction) {
            if (empty($data->require->{$instruction})) {
                $dependencies[] = $instruction;
            }
        }
    } else {
        $dependencies = iterator_to_array($parser);
    }
} else {
    if (!is_dir($dir)) {
        mkdir($dir, 0755, true);
    }
    $dependencies = iterator_to_array($parser);
    if (empty($dependencies)) {
        file_put_contents($composer_json, '{}');
        system("composer dumpautoload -d {$dir}");
    }
}

if (count($dependencies)) {
    $packages = implode(' ', $dependencies);
    system("composer require -d {$dir} {$packages}");
}

$autoloader = "{$dir}/vendor/autoload.php";
array_splice($argv, 0, 2);
$args = implode(' ', $argv);
system(PHP_BINARY . " -d auto_prepend_file={$autoloader} -f {$file} {$args}");

test.php

<?php
declare(strict_types=1);

# phps ramsey/uuid
# phps hashids/hashids

use Ramsey\Uuid\Uuid;
use Hashids\Hashids;

$uuid = Uuid::uuid4()->toString();

$hashids = new Hashids($uuid);
$id = $hashids->encode(1, 2, 3);
$numbers = $hashids->decode($id);
echo implode(' ', $numbers), PHP_EOL;